The present invention relates to the orientation of conduits (e.g., casings or tubings) in well-bores.
Deviations from vertical well-bores and horizontal well-bores are used in oil and gas production, and the lengths of casing and tubing strings used are quite long. Further, there is a desire for instrumentation in well-bores. However, accurate installation of instruments outside a casing or a tubing is difficult. In addition, regardless of the accuracy of installation, the ability to accurately know where an instrument resides with respect to some reference (e.g., a vertical reference) is also difficult; and, even when an instrument is not used outside the casing, it is desirable to know the location of various attributes of the casing or tubing with respect to some reference.
Various attempts to orient tools within an installed casing or tubing have been proposed. For example, see U.S. Pat. Nos.: 6,173,773; 6,089,320; 6,070,667; 6,003,599; 5,964,294; 5,454,430; 5,394,941; 5,335,724; 5,318,123; 5,285,683; 5,273,121; 5,107,927; 5,010,964; 4,637,478; 4,410,051; PCT,IB00/00754 (WO 00/75485); 4,869,323; 4,194,577, all of which are incorporated herein by reference. However, there is still a need for methods, systems, and devices, for accurate orientation of casings and/or tubings in well-bores and for accurate knowledge of the orientation of the casings and/or tubings in the well-bores.